1. Field of the Invention
This invention relates to a linear blind broaching machine for progressively broaching blind shapes in a workpiece.
2. Background Art
Blind broaching machines for the most part in the past have utilized rotary tables on which progressive tools are mounted to provide progressive broaching of a blind shapes in a workpiece. Such blind broaching may be used to form splines or other shapes and may be either internally within a blind hole or externally adjacent a flange as other external blind formation. The workpiece is conventionally held by a vertically moving ram that is mounted on a ram support of a ram assembly and the progressive tools are mounted on the rotary table such that rotary indexing thereof moves the next tool below the workpiece whose downward movement on the ram then provides the next broaching step in the progressive blind broaching. Such rotary blind broaching is disclosed by U.S. Pat. Nos. 4,401,401 Roseliep and 4,917,551 Roseliep. Also, rotary index tables that can be utilized in such rotary blind broaching are disclosed by U.S. Pat. Nos. 5,450,771 Carter et al., 5,635,808 Roseliep and 5,682,658 Roseliep.
A tool holder that can be utilized in blind broaching is disclosed by U.S. Pat. No. 5,878,642 Roseliep, and a loading/unloading system utilized in blind broaching is disclosed by U.S. Pat. No. 5,315,750 Roseliep. Also, a mechanical drive linkage for a ram of a blind broaching machine is disclosed by U.S. No. Pat. No. 5,919,015 Mason et al.
Progressive blind broaching machines have also previously been of the linear type having a linear tool slide that is mounted on a base for horizontal indexing movement below a broaching ram of the broaching ram assembly. The broaching ram is mounted for vertical movement on a ram support and supports the workpiece. Each downward stroke of the broaching ram provides blind broaching and upon subsequent upward movement, the linear tool slide is indexed horizontally in a rectilinear direction to present the next tool below the workpiece for the next progressive broaching stroke.
An object of the present invention is to provide an improved linear blind broaching machine.
In carrying out the above object, the linear blind broaching machine includes a base for mounting on a factory floor and the broaching ram assembly including a ram support extending upwardly from the base. The broaching ram assembly includes a broaching ram mounted by the ram support for vertical movement that moves a workpiece to be blind broached.
According to one aspect of the invention, a pair of spaced linear antifriction bearings including roller elements support the linear tool slide on the base for horizontal indexing movement under the broaching ram for progressive blind broaching of the workpiece. Each linear antifriction bearing includes an elongated guideway mounted on the base in a spaced and parallel relationship to the guideway of the other linear antifriction bearing. Each antifriction bearing also includes a roller carriage on which the linear tool slide is mounted at a spaced location from the other linear antifriction bearing. Each antifriction bearing also includes roller elements that support the roller carriage thereof on its elongated guideway. A support block is mounted between the pair of linear antifriction bearings and between the base and the linear tool slide below the broaching ram to provide support to the linear tool slide during the blind broaching and thereby prevent overloading of the roller elements of the linear antifriction bearings.
In one construction, the support block of the blind broaching machine is fixedly mounted on the base. This fixedly mounted support block preferably has a clearance with the linear tool slide, and the linear tool slide deflects during the broaching to prevent overloading of the roller elements of the antifriction bearings. The linear tool slide includes wear blocks positioned below the blind broaches to engage the fixedly mounted support block and provide support to the linear tool slide during the broaching. In another construction, a wedge is actuated to provide the support of the support block between the base and the linear tool slide during each broaching movement of the broaching ram.
According to another aspect of the invention, the linear tool slide has an elongated construction that extends horizontally to support progressive blind broaches and includes an elongated positioning block having a flat surface against which the blind broaches are positioned so as to be accurately positioned laterally along the elongated direction of the linear tool slide. An electric servomotor of the machine drives the linear tool slide along the linear antifriction bearings to provide indexing thereof between broaching movements of the broaching ram.
The linear blind broaching machine as described immediately above preferably has a set of spring biased locators that position the blind broaches against the flat surface of the elongated positioning block. Furthermore, the machine also preferably includes a set of stops for positioning the blind broaches along the length of the linear tool slide. The set of spring biased locators most preferably position the blind broaches against the flat surface of the elongated positioning block and against the set of stops and thereby establish both lateral and longitudinal positioning of the tool profiles on the linear tool slide.
In accordance with another aspect of the invention, the linear blind broaching machine includes a roller screw drive that connects the ram support and the broaching ram of the broaching ram assembly, and an electric servomotor drives the roller screw drive to move the broaching ram for the linear blind broaching.
The linear blind broaching machine also includes linear antifriction bearings that mount the broaching ram on the ram support for the vertical movement that moves the workpiece to be blind broached. These linear antifriction bearings that mount the broaching ram cooperate with the linear antifriction bearings that support the linear tool slide on the base for horizontal indexing movement under the broaching ram to permit accurate control of the broaching and indexing movements. Furthermore, the actuation of the linear tool slide is effectively performed by the electric servomotor previously mentioned to accurately control the indexing movement.
All aspects of the linear blind broaching machine as described above and when utilized with each other provide efficient and effective blind broaching.
The objects, features and advantages of the present invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings.